The present invention relates to an improved package for dispensing individual sheets of material from a stack. In particular the present invention relates to an improvement in biasing devices for urging a stack of sheet material toward an opening of the package.
Packaging previously has been developed to hold a stack of sheet material and permit dispensing of individual sheets of the material one at a time. The packaging characteristics depend on the manner in which the stack of sheet material is formed. For example, where the successive sheets of material in a stack are connected to one another along alternating opposing edges by a peelable adhesive (e.g., in a Z-fold manner), packaging has included a six-sided container with an opening in one side for removing individual sheets from the stack. Successful single sheet dispensing from such package requires that the stack be urged toward the opening, even as the sheets in the stack are being depleted. Various ways of urging the stack toward the opening have been proposed.
In U.S. Pat. No. 4,586,631, which is owned by a common assignee with the present application, a piece of foam material is compressed and placed in the packaging behind the bottom of the stack. The foam material provides a force to urge the stack toward the opening as individual sheets are removed from the packaging.
In U.S. Pat. No. 4,653,666, also owned by a common assignee with the present invention, a spiral wire spring compressed and placed between the stack and the base of the packaging provides the force necessary to lift the stack as individual sheets are dispensed.
The present invention constitutes an improvement over prior biasing devices for dispensing individual sheets from a Z-folded stack of sheet material from a container.
The present invention provides an improved means for biasing a stack of sheet material within a dispensing package, wherein the stack of sheet material comprises a plurality of vertically aligned sheets of material which are releasably adhered to each other along opposite edges of successive sheets by a narrow band of pressure-sensitive adhesive, and wherein the dispensing package comprises a bottom, side walls and a top, the top defining an opening that extends between opposing side walls. The inventive biasing device comprises a sheet of material sized to fit within the dispensing package between the stack of sheet material and the bottom of the dispensing package. An elastomeric element, having an unstressed length that is less than a length of one edge of the sheet of material, is positioned between opposing first and second edges of the sheet, and secured to opposing sections of the sheet. The elastomeric element thereby draws the first and second edges of the sheet toward one another and elevates a central portion of the sheet of material.